Silicate problem in RO water

[brandon0921]

Ive been struggling with diatoms in my 2yr old tank and have identified the source as being silicates coming from my RO water. Since discovering the source, I upgrade from a 4 stage to a 7 stage RODI system with booster pump, auto flush, and 2 new membranes. For the DI canisters, Im using anion in the first stage then TWO silicate buster cartridges in the final 2 slots (now 2 anion then a silicate buster). The first month running this setup, silicate levels in the RO water dropped to 0 and tank silicates down to 200ug/l from 450, with the diatoms noticeably getting better. Thought I had beat it. A month later, diatoms are making a come back and so are the silicates. This months ICP came back showing 40ug/l in the RO water and 450 in the tank once again.

Is there anyway to resolve this short of running gfo in the display system? Id prefer not to do this as I am already feeding heavily to keep po4 around .04 in an SPS dominated tank and livestock is happy.

 

[brandon0921]

Few pictures of the diatoms

 

[thatmanMIKEson]

Ever beat those dirty diatoms? Nice build! Love the h.w

 

[brandon0921]

Ever beat those dirty diatoms? Nice build! Love the h.w

Thanks! And yes,I did. Long story short I worked with spectrapure who are true experts in water filtering. The double membranes with the 75psi restrictor wasnt producing a proper waste to product water ratio. They have me make a couple changes to the order of the filter system, add additional tds meters, along with a different flow restrictor on the waste line. It’s a lot to explain, but I can share pictures. Best to reach out the them if you’re beating your head against the wall like I was. They were beyond helpful in getting everything sorted out

 

[brandon0921]

 

[thatmanMIKEson]

Nice! Thanks for the information that helps ill check out their resins I see they have a silicate buster

I'm just starting the process of putting my finger on my possible silicate issues, I already switched to 123pro d.i resin from brs, I just ordered a salifert silicate test (although I also just seen Hanna has a few tester options). I am wondering about my storage containers possibly leaching silicates.

First I guess for me is testing, how did you go about discovery and testing?

 

[Hot2na]

talk to spectrapure about a high silicate removal membrane

 

[thatmanMIKEson]

talk to spectrapure about a high silicate removal membrane

Ok, for the r.o membrane? Does that happen to fit in the brs r.o unit i have already?

Thanks for the advice!

 

[Hot2na]

I believe it WILL

 

[thatmanMIKEson]

I believe it WILL

Thanks, I just ordered a single stage d.i add on from spectra pure that comes with the regular silicate buster cartridge.

I'm not seeing anything labeled specifically for silicates on their r.o membranes but I may give them a try next membrane I run, i just replaced these getting 3tds I replace both @ 4-5tds

I guess i should put the silicate buster in #4 spot in line with the resins just before storage containers.?or first in line if its high silicates coming from r.o.., I don't burn thru resin thats what has me looking at the storage.

Then I guess some silicate testing before and after it goes into storage will tell me if its in the water im producing, or coming from the storage containers.

 

[brandon0921]

I ATI ICP every 6 weeks. They test RO and tank water. Kept seeing nitrate and silicates creeping in on the RO results. Once I tested directly from the line I knew it wasn’t leeching from the storage container.

 

[thatmanMIKEson]

I ATI ICP every 6 weeks. They test RO and tank water. Kept seeing nitrate and silicates creeping in on the RO results. Once I tested directly from the line I knew it wasn’t leeching from the storage container.

Ok same plan I was thinking im going to start off cheap with salifert test first. Ive never had a icp test done yet, im more scared of the results than the price, but that is probably my next step if questions or concerns come up from my testing.

Thanks for the info Brandon!

 

[GARRIGA]

Wouldn’t it be practical to run GFO prior to DI?

 

[thatmanMIKEson]

Wouldn’t it be practical to run GFO prior to DI?

I'm not sure i follow what your suggesting?

Have you done this?

I would think the gfo would disintegrate and ruin any d.i resin its f.o(ferric oxide)

But maybe on the mixed fresh water with a lower flow..

Is this what you were thinking or have done?

 

[GARRIGA]

I'm not sure i follow what your suggesting?

Have you done this?

I would think the gfo would disintegrate and ruin any d.i resin its f.o(ferric oxide)

But maybe on the mixed fresh water with a lower flow..

Is this what you were thinking or have done?

I’m not going the RODI route. My tap is actually pretty good and tested every hour by my municipality plus contains high levels of calcium and magnesium I don’t want stripped out. Going with Ultrafiltration as it removes everything down to a parasite but likely not silicates. For that I was going to go with PhosGuard but having second thoughts based on possible aluminum and now considering the option of mixing GAC with GFO and running that instead. Since that’s an approach already in use for using GFO and not grinding then perhaps it would work in my application as well as RODI since neither are moving much water fast. Has to be cheaper than burning through DI.

 

[thatmanMIKEson]

I’m not going the RODI route. My tap is actually pretty good and tested every hour by my municipality plus contains high levels of calcium and magnesium I don’t want stripped out. Going with Ultrafiltration as it removes everything down to a parasite but likely not silicates. For that I was going to go with PhosGuard but having second thoughts based on possible aluminum and now considering the option of mixing GAC with GFO and running that instead. Since that’s an approach already in use for using GFO and not grinding then perhaps it would work in my application as well as RODI since neither are moving much water fast. Has to be cheaper than burning through DI.

I'm not sure about that but if it works for you thats great! Sounds like you have a plan, I need to figure out my plan also.

Thanks for your input on this